The long-range objective is to understand the molecular basis of cytoplasmic streaming and contractility and its regulation. Therefore, I wish to continue my work on regulation of contractility in Physarum. Preliminary hybridization work with the scallop system shows that one light chain from Physarum myosin can combine with light-chain depleted scallop myofibrils. We will study whether this light chain can be phosphorylated and/or whether the heavy chain can be phosphorylated and if such modifications alter actin activation. Continue the study of the formation of actin filaments from non-filamentous precursors by 5'AMP, specifically to further our hypothesis that a polyphosphate donor is involved and to see if the 5'AMP acts on the actin-actinin dimer present in the extract. Study cytoplasmic myosin localization in resting and active secretory cells, neuroblastoma, and retina using our antibody to cytoplasmic myosin. Begin a study of the mechanism of phagocytosis, using the retinal pigment epithelial cell.